Orvis fly line backing is braided Dacron on spools, precision processed with uniform strength. 20-lb. test is for trout, bass and most freshwater fly fishing.
This high-visibility fluorescent orange flyline backing lets you see the backing in the water when a big fish takes out line in a hurry. Tested extensively by Orvis' saltwater guides, who found the flyline backing helped them know where a fish was and when it was changing direction. The round Dacron backing won't rot or mildew and stores well on the fly reel.